1. Field of the Invention
The present invention relates to a method and circuit for receiving signals, and more particularly, to a signal receiving method for determining a transmission format of an input signal and a related signal receiving circuit.
2. Description of the Prior Art
In general, signal transmission formats of transmission interfaces in modern digital video players are mainly high-speed video signal transmission formats such as the high-definition multimedia interface (HDMI) transmission format and Display Port interface transmission format. If it is required to support multiple signal transmission formats of digital transmission interfaces mentioned above in the same integrated circuit (IC), the prior art has to implement a plurality of sets of specific pins respectively corresponding to each of the digital transmission interfaces, or provide a plurality of sets of hardware to individually process input signals of the different digital transmission interfaces. Thus, there will be disadvantages of increasing the number of pins and the IC area for the prior art. It is obvious that the conventional signal receiving circuit is not capable of determining transmission formats of the input signals correctly.
However, both of the high-speed digital video signal transmission formats mentioned above use a differential signal transmission technology of differential pairs to attain purposes of transmitting the digital video signals in high speed. Please refer to FIG. 1 and FIG. 2 together. FIG. 1 shows a pin definition table of the HDMI in accordance with the prior art. FIG. 2 shows a pin definition table of the Display Port interface in accordance with the prior art. As shown in FIG. 1 and FIG. 2, the HDMI uses the pins number 1, 3, 4, 6, 7, 9, 10, 12 to transmit the digital video signals in high speed, and the Display Port interface uses the pins of number 1, 3, 4, 6, 7, 9, 10, 12 to transmit the digital video signals in high speed. In other words, the two high-speed digital video signal transmission formats use four differential pair pins as main input terminals for transmitting the digital video data thereof. In addition, since the specification documents of the HDMI and the Display Port interface are known in the related field, they can be referred for the related descriptions about the pins shown in FIG. 1 and FIG. 2, and thus further explanation of the details about the pins are omitted herein for the sake of brevity.
Since there are some differences and different characteristics between the HDMI and the Display Port interface, thus how to properly use the differences and the different characteristics between the HDMI and the Display Port interface so as to let a signal receiving circuit having the input interface including a plurality of common input terminals corresponding to the different transmission formats be able to correctly determine a transmission format of an input signal is the key point that the present invention is about to disclose.